<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title><script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
  <style>
    .setColor{
      color: rgb(184, 33, 171);
    }
    .setFontSize{
      font-size: 38px;
    }
  </style>
</head>
<body>
  <div id="app">
    <div :class="[index1,index2,index3]">欢迎你的巴子</div>
 </div>
 <script>
     let vm = new Vue({
         el: "#app",
         //data指的是model
         data() {
             return {
              index1:'setColor',
              index2:'setFontSize',
             }
         }
     });
 </script>
</body>
</html>